1. Field of the Invention
The present invention relates to an antenna device and an antenna system, and particularly relates to a dipole antenna device and a dipole antenna system.
2. Description of the Prior Art
The antenna utilized in a conventional 2.4-GHz wireless LAN or in a system using a 802.11b/g/n dipole antenna is usually an external antenna with a plastic or rubber sleeve surrounding it. Such antennas, on average, have a height of 8 to 10 cm and are located on one side of an apparatus, prone to be vandalized, and affect the aesthetic look of the apparatus. Additionally, a conventional internal dipole antenna is a printed antenna structure, and a signal is fed to the antenna via a mini-coaxial cable. However, since the two radiating metal pieces of the antenna are separate, the antenna can not be manufactured from a single metal plate, giving the printed antenna a higher cost. Related U.S. Pat. No. 6,621,464B1, U.S. Pat. No. 6,624,793B1, US20060284780A1 disclose a “dual-band dipole antenna.” The dual-band dipole antenna obtains a dual-band operation by inserting slits or slots thereon and changing the length of the radiating metal piece. However, the above-mentioned antennas all have separate antenna radiating metal pieces, such that the manufacturing thereof must use a printed circuit process, thereby increasing the manufacturing cost of the antenna.